Off the top of my head here are candidates...
Behre (S) - can he make it back?
Miles (S) - a possibility if Behre can't make it back. You can probably find similiar guys out there like him but he does have the luxury of being with the team and understanding the defense.
Casillas (LB) - practicing but not cleared for contact.
Wade (CB) - not sure if his 'injury' would qualify?
Washington (WR)- caught in a numbers game at wide reciever but the reality is that I would take Parker, Jones and Davis over him. Talley might be available later on if an injury or two hits.
Jones (C) - Beatty should be getting a roster spot around the time where Jones would be able to come back. If we needed both in that time period, we are probably in trouble. Relying on an undersized rookie coming off an injury doesn't sound to be sound. He's probably a better bet for a long term injured reserve.
Brown (K) - God forbid.
My bet (and hope) would be Behre. I think Wade probably makes the team. You need to come up with your final 53 so it probably make sense to cut a safety anyway to get there and then they can sign someone (the safety that they cut probably would be available especially if there is some sort of agreement) after they make the move to Behre. I would hope that Casillas is healthy enough to play soon. If not, he would be a candidate. He probably makes sense as the candidate if there isn't a chance that Behre can return.
The possibility nobody wants to think about is Beason.
And hopefully they don't use it.
Berhe has played 50 snaps on defense in the NFL, you don't waste returnable IR on that guy IMO. Especially since he might just be out 4 weeks.
Returnable IR IMO should be for someone more important than any of those names.
Cruz is the only candidate I think makes sense....IF his calf injury is expected to linger for 6 weeks. If not no one injured yet makes that much sense.
I also forget about Beason. So we have lost a lot of safeties to year ending injuries but the potential good news is that most of our players left are getting healthy. We can probably hold off as only the top 47 dress.
If the team thinks he can be back in early October as he said would he be a candidate? Wondering more from a theoretical standpoint.